Method of making ice in small pieces



NOV. 18, 1947. F M RAVER 2,431,278

METHOD OF MAKING ICE IN SMALL PIECES Filed Nov. 18, 1942 fm1 .l.3d 32 30 bmw ATTORNEY Patented Nov. 18, 1947 METHOD OF MAKING ICE IN SMALL PIECES Francis M. Raver, York, P., assignor to Flakice Corporation, Brooklyn,

Delaware N. Y., a corporation of Application November 18, 1942, Serial No. 465,955

2 Claims. 1 This invention relates to method and apparatus for continuously removing brittle substance from a rigid freezing surface on which said substance \i-s continuously congealed from a fluid state. More particularly, the invention relates to the manufacture of ice pieces for refrigeration purposes, said pieces having extensive width and length dimensions, and small thickness dimensions, whereby said ice pieces present maximum surface area per unit of mass and maintain substantially constant surface area during 90% of the melting of the ice pieces. f An object of the present invention is to provide improved method and apparatus for manufacturing ice pieces by freezing water on a rigid cylindrical surface and removing ice therefrom in the form of pieces as above described.

The invention accordingly consists .in the features of construction, combinations of elements, arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others, all as will be illustratively described herein, and the scope of the application f which will be indicated in the following claims.

In the drawings:

Figure 1 is a perspective View of apparatus embodying the invention;

Figure 2 is a reduced vertical axial cross-section of the cylinder of Figure 1; and Figure 3 is a diagrammatic perspective View of a portion of an ice layer being freed from the surface on which it is frozen.

Referring to Figure 1, a tank or compartment IIJ is shown for holding water to be frozen. Rotatably supported in the tank so as to be more than 50% submerged is a freezing cylinder, generally .indicated at Il, having a cylindrical freezing surface I2.

Referring to Figure 2, the cylinder is suitably mounted on a shaft I5 supported in bearing assemblies I3 and I4, the right hand one I3 of which is broken away to show its general construction. This assembly is identical to that shown in my U. S. Patent 2,344,922, issued March 21, 1944, and is adapted to permit passage of refrigerant to and from the cylinder. The left hand bearing I4 is of the usual construction to prevent flow of water from the tank along the shaft I5.

The shaft I5 is provided with an outer concentricy passage I8 for conducting liquid refrigerant from a compressor and condenser system, diagrammatically indicated at I6, into the evaporating space of the cylinder. The liquid refrigerant is conducted to the concentric passage through a pipe I1. The shaft assembly is provided with an inner concentric passage I9 to conduct spent refrigerant from the cylinder to a pipe 20 which takes the spent refrigerant back to the system I6.

The cylinder is continuously rotated by means of a gear 2l, secured to the shaft I5, and driven through a suitable pinion 22, driven by an electric motor 23, provided with a suitable change speed reducing gear.

The temperature inside the cylinder is maintained at whatever temperature is desired in any suitable manner, or by the usual differential valve controlling the flow of liquid refrigerant to the evaporator in response to the temperature of the spent refrigerant and to the pressure of the spent refrigerant.

. The Water in the tank is maintained at the desired level by any suitable vmeans, such as, a float valve (not shown). The makeup water controlled by the float valve is supplied through a pipe 24 emptying directly into tank I0.

As the cylinder Il rotates, an ice sheet builds up on the submerged portion of the surface I2, and as 4the ice sheet moves out of the water it passes under a cutting unit, generally indicated at 29, which in appearance resembles a lawn mower cutter. As the ice sheet passes under the cutting unit, successive leading portions of the ice sheet are severed from the-'ice sheet and are freed from the surface I2 in the form of ice pieces having relatively large length and width dimensions and relatively small thickness dimensions as above described.

The thickness of the ice sheet and of the resulting pieces depends on the speed of rotation of the cylinder, providing the rate of refrigeration of the cylinder is kept constant. If the speed is increased, the thickness is reduced and vice versa. The speed may be set by the reducing gear unit provided with the driving motor.

The cutting unit has a plurality of helically shaped blades, and is mounted on a shaft 3| which rotates in bearings 30. The axis of shaft 3| is directly above and parallel to the axis of the cylinder II. The shaft 3I is so adjusted with respect to the cylinder I I that the sharp beveled edges of the helical blades very nearly contact, but do not touch the surface I2, as the cutting unit and cylinder rotate.

On the shaft 3| supporting the cutting unit is secured va pinion gear 32, driven by another pinion 33, which in turn is driven by a motor 34 provided with a suitable change speed reduction unit so that the surface (peripheral) speed of the cutting unit and the surface speed of the cylinder I I may be adjusted relatively to each other. The drive is such that as each blade approaches the surface I2, the blade is travelling in the same direction as the surface I2.

As the cylinder turns, the ice pieces that are freed by the cutting unit are taken off of the cylinder by a doctor 35, located above the water level in the tank I0.

Referring to Figure 3, the operation of the ice cutting unit is diagrammatically illustrated. The ice sheet A formed on the cylinder surface I2 has a thickness B. The blade 29a has just severed an ice portion C from the ice sheet A and has freed the ice portion from the surface I2. The ice portion is broken up into pieces D during the operation, which pieces will subsequently slide off on the doctor 35.

The problem of removing ice from a rigid surface on which it is frozen has long been recognized as a diflcult one. Scraping ice from such a rigid surface is an unsatisfactory method in that it produces only small particles of ice, commonly called mush ice, and such ice can be handled practically only by mixing it with water or compressing it into briquettes.

In an application having Serial No. 187,761, filed January 29, 1938, (now issued as U. S. Patent No. 2,310,468) Frank Short disclosed a novel method andA apparatus for removing ice in the form of pieces, such as above described, from a rigid surface on ,which the ice is frozen, by exerting on' an ice sheet formed on a rigid cylinder surface a force acting along a line spaced inwardly from but parallel to the leading edge of the ice sheet. The force has a component action to sever the portions thus segregated from the ice sheet, and a component action through the body of the ice portion to overcome the bond of adhesion between the ice portion and the surface, without overcoming the compressive strength of the ice portion; i. e., without breaking it into ice particles. In the Short apparatus the force was applied by a blade moving radially into the ice sheet while having no circumferential component of motion with respect to the ice sheet.

I have discovered that by applying the force through the medium 'of a blade that has a pe-A ripheral speed `greater than that of the ice sheet on the cylinder, improved results can be obtained in the freeing of the ice pieces from the cylinder, in that a thinner ice sheet may be operated on by the cutting unit to satisfactorily remove the ice in the desired form of ice pieces. This makes the apparatus more economical because within limits the thinner the ice sheet the greater is the production capacity of the apparatus. This follows because as the ice sheet increases in thickness, it offers very much greater resistance to heat flow through it and the freezing rate of the ice is reduced. Also thin ice pieces are desirable because their melting rate remains more constant than that of thicker ice pieces.

To this end, in the present embodiment the blades of the ice cutting unit are positively driven and at a rate to give the blades a surface or peripheral speed greater than that of the cylinder. As the ratio of the peripheral speed of the cutter to the peripheral speed of the cylinder is increased from a ratio of 1:1, the ice removal of the ice cylinder improves until the ratio becomes so high that the cutting unit acts as a shaving apparatus instead of an ice piece removing apparatus. o

In one specific embodiment of the invention in which the cutting edges of the blades were beveled, as shown in Figure 1, and in which the blade edges had a radius of 12.5/32 inches (with reference tothe axis about which the blade edgesv turn), and in which the surface of the cylinder had a radius of 9 inches, the ice sheet approximately one eighth inch thick was not removed or freed by the cutting unit and was not re- `moved by the doctor 35 until a ratio of peripheral speed of the blade to vperipheral speed of the surface I2, of 3:1 was reached; i. e., in which the peripheral speed of the :blades was three times faster than that of the cylinder. But at this ratio and up to a ratio of 5:1, although the ice was not entirely freed by the cutter, it was sufficiently loosened so that the collecting blade or doctor 35 removed it from the surface I2. 'I'his operation was obtained with a circumferential spacing between the edges of the blades of 12,5/64 inches. This same satisfactory operation was obtainedy with a circumferential spacing of the blades of 411/64 inches. This circumferential spacing of the blades was obtained by removing from the eight bladed ice cutting unit 29, shown in Figure 1, two adjacent blades thereby increasing the spacing .between the two blades that bordered the removed blade to k411/64 inches. Thus, increasing the spacing between these two cutting blades, increased the widthr of the ice edge portion removed by the following of these blades so that larger ice pieces were produced.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, itis to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Iclaim:

l. The method of producing ice in small pieces which comprises: progressively freezing a mass of water into a thin sheet of ice curved about and traveling about an axis of rotation located parallel to the unfrozen surface of the mass of Water; and in a zon'e located above said mass and in the path of travel of said sheet successively separating relatively narrow elongated sheet portions having substantially parallel sides by making a succession of indentations along similar, spaced lines extending from one side edge of the sheet to the opposite side edge thereof and successively imparting to each sheet portion lying in front of each indentation a linear velocity three to ve times as great as the linear velocity of the curved sheet behind such indentation.

2. The method of producing ice in small pieces which comprises: progressively freezing water separating relatively narrow elongated sheet lportions having substantially parallel sides from such sheet by making a succession of indentations along similar, spaced lines extending from one side edge of the sheet to the opposite side edge thereof and imparting to each sheet portion lying in frnt of each indentation a linear velocity three to five times as great as the linear velocity 0f the curved sheet :behind such indentation.

l FRANCIS M. RAVER.

REFERENCES CITED The following references are of' record in the file of this patent:

Number Number UNITED STATES PATENTS Name y Date Gay June 19, 1934 Raver Mar. 21, 1944 Raver Jan, 19, 1943 FOREIGN PATENTS Country Date Germany 1 May 27, 1938 Great Britain Aug. 10, 1874 

